| Name | Info | Provider | Link |
|---|---|---|---|
| Medicare | free resource | MedlinePlus Health Information | https://medlineplus.gov/medicare.html |
| subscription/membership/fee required | Ovid Technologies, Inc. | http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=19674430.ui | |
| free resource | PubMed Central | https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/19674430/ | |
| free resource | Europe PubMed Central | https://europepmc.org/abstract/MED/19674430 | |
| subscription/membership/fee required | Wiley | https://doi.org/10.1111/j.1475-6773.2009.00964.x |